184 PROCEEDINGS OF THE ACADEMY OF [Feb., 



Lncina (Divaricella) dalliana n. sp. PI. V, figs. 10. 11. 



Shell almost circular, somewhat truncate posteriorly, nearly 

 equilateral, moderately convex, shining white, ))orcellanDus, sur- 

 face sculpture divaricate; in full-grown examples there is a smooth 

 band where the diverging lines would meet. The beaks aie 

 slightly raised above the hinge line, directed forward and located 

 hardly in advance of the centre; they are sculptured with micro- 

 scopic concentric strife only which are ^vorn off in the largest speci- 

 men we have. The luuule i? about one-eighth the length of the 

 shell The anterior area under the lunule is not distinctly marked. 

 The groove of the ligament is long and narrow. The margin 

 has the interior layer very finely cn^nulate, but the outer layer 

 smooth. The hinge of the right valve is provided with a heavy 

 cardinal tooth with a pit on each side, and a single tubercular 

 anterior and posterior lateral, the posterior one being about twice as 

 far from the beak as the anterior one. The muscle scars are of 

 moderate size, the anterior one being long and narrowr, while the 

 posterior one is more elliptical, 



Alt. 19, diam. 20, thickness of right valve 4.5 mm. 



Alt. 21, diam. 22.5, thickness of right valve 5.5 mm. 



Locality. — In ballast from South Africa. 



Types in the collection of the Academy of Natural Sciences of 

 Philadelphia, No. 79,380, collected by Mr. J. G. Malone. 



This species is distinguished from L. dentata Wood by not 

 having the outer layer of the margin heavily dentate; from L. 

 cumingii A. and A. in having the diverging sculpture extending 

 across the anterior area to the lunule, and the inner layer of the 

 margin is crenulate; from L. quadrisulcata Orb. in having a smooth 

 band where the diverging lines would meet in full-grown examples; 

 from L. hidtojiiana n. sp. in having the inner layer of the margin 

 crenulate, and in the smooth band. 

 Luoina (Divaricella) huttoniana n. sp. PI. v, figs. 14, 15. 



Shell almost circular, posterior extremity squarely truncate, 

 nearly equilateral, bluish white with white concentric streaks, 

 glossy, porcellanous, surface sculpture divaricate, the diverging 

 sculpture extending to the edge of the comparatively broad ante- 

 rior area below the lunule. The beaks are slightly raised above 

 the hinge line, directed forward, located slightly in advance of 

 the centre, sculptured with rather coarse close concentric costellse 



